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(CNN) -- Hilary Duff says her new album is “very positive” but admits that it started out “a lot heavier and a lot darker” because of the separation from her husband, Mike Comrie.

“I’m separated from my husband right now, which has been a very difficult thing to go through,” she told Billboard’s “Pop Shop” podcast. “In the beginning, the album was a lot heavier and a lot darker, because I had to get that out. Once I did get that out, a lot of fun came.”

Duff married Comrie, a former pro hockey player, in 2010 after dating for three years. Their son, Luca, was born in 2012. Duff and Comrie announced their separation in January.

Duff, 26, admits that she’s “nervous” after being away from music for seven years. Her just-released single, “Chasing the Sun,” is from her still-untitled album, which will be her first studio release since 2007’s “Dignity.”

She says she first started thinking of new material when she was pregnant with her son. After having the child and taking another year, she was even more anxious.

“I felt like I was missing a big part of myself,” she said.

Duff established a successful singing career on the heels of her popular Disney show, “Lizzie McGuire,” which aired from 2001 to 2004. She spent most of her teenage years touring and says that turning 20 was a big factor in leaving the road.

“It was time for me to be a person, and the break just ended up being a long time,” she said.

One song on the album has to do with the loneliness she felt after being surrounded by dozens of people during her peak. Another song is a collaboration with Ed Sheeran.